Project Summary/Abstract: This Phase I proposal addresses the dire need for continuous on-line monitoring of urea concentration within dialysate fluid to gauge dialysis adequacy. At present, patients are dialyzed for a fixed amount of time. However, if the waste concentration within the patient's body is very high, the fixed dialysis time may result in underdialysis. On the other hand, if the patient has lower waste concentration within the body, the fixed dialysis time may result in overdialysis. Either scenario may result in several health problems, such as widespread organ failure due to consistently high toxin levels (underdialysis) or dangerously low electrolyte concentration (overdialysis). These health problems lead to increased morbidity and mortality amongst the dialysis population. Urea is a sensitive marker of waste level within the patient's body. By measuring the urea level continuously during the dialysis session, a sound judgment may be made as to the optimal dialysis time. In order to continuously monitor the urea levels within the dialysate, we propose to demonstrate colorimetric soft hydrogel films, which will change color with change in urea concentration. These novel colorimetric materials promise to be rugged, reliable, inexpensive, easy to mass produce and use for on-line continuous dialysis adequacy monitoring. During the Phase I effort, we will perform feasibility studies to prove that our colorimetric gels can reversibly and reproducibly monitor changing urea levels in a simulated dialysate fluid, using a pre-prototype device which we will assemble during Phase I. During Phase II of this effort, we will optimize the dynamic urea response range and longevity of the urea sensor in actual dialysate fluid. During Phase II, we will also prepare an actual prototype urea profiler which will automatically provide urea clearance profiles and other parameters of dialysis adequacy such as CB Equil and Kt/V. The prototype will be capable of being directly hooked up to existing dialysis lines and will be an independent stand-alone and miniature device for actual dialysis adequacy measurement to maximize the productivity of each dialysis session. We will team up with Nephrology centers nationwide, during and beyond Phase II to test and validate our on-line urea monitor in actual dialysis clinics. If successful, this technology, in the long term, will be of great benefit to the patient population relying on dialysis. Project Narrative: Our proposed on-line urea profiler for dialysis will directly benefit the hundreds of thousands of patients who rely on routine dialysis to survive. By maximizing the productivity of every dialysis session, the proposed urea monitor will ensure improved long-term health and length of life of renal failure patients. Clinicians will also benefit from this new user-friendly, inexpensive and fully automated technology to greatly improve the way in which they manage their dialysis patients. [unreadable] [unreadable] [unreadable]